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1.
Prev Vet Med ; 208: 105765, 2022 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-36181748

RESUMO

Early and accurate diagnosis is fundamental for successful surveillance and control of maedi-visna virus (MVV). MVV was detected in Norway in 2019, almost 14 years after the previous outbreak. Genetic analysis indicates persistence of the virus in the sheep population since 2005. The virus was not detected despite continuous serological surveillance. This emphasises the need for improved surveillance, which relies on an understanding of both diagnostic test performance, sampling strategy and the prevalence of the disease. This study therefore aims to evaluate three commercial ELISA tests for MVV antibodies. We conducted a retrospective study using 615 samples from six flocks diagnosed with MVV in 2019. We ran all samples with the following three tests: ID Screen® MVV/CAEV Indirect (IDvet, Grabels, France), IDEXX MVV/CAEV p28 Ab Verification Test (IDEXX Laboratories, Maine, USA) and Elitest MVV/CAEV (Hyphen Biomed, Neuville-sur-Oise, France), hereinafter referred to as ID Screen, IDEXXp28 and Elitest respectively. Without a perfect reference test, we used Bayesian latent class analysis, including conditional dependence between tests, to estimate diagnostic accuracy and true prevalence in the flocks. Using recommended cut-off values, we found that ID Screen and Elitest had significantly higher sensitivity (Se) estimates (99.3 % [97.4-100.0, 95 % Posterior Credible Interval] and 97.4 % [94.1-99.7 %], respectively) than IDEXXp28 (79.5 % [72.3-86.0 %]), while IDEXXp28 and ID Screen had significantly higher specificity (Sp) estimates than Elitest (99.7 % [99.1-100.0], 99.1 % [98.0-99.8 %] and 93.7 % [91.4-95.7 %], respectively). The estimated true prevalence in the six flocks ranged from a median of 0.8-93.5 %. Combining ID Screen and Elitest in serial interpretation showed the highest median Se and Sp (96.7 % [92.0-99.1] and 100.0 % [99.9-100.0], respectively), as well as the highest median positive predictive value (PPV) for the population with the lowest prevalence. Our study supports the use of ID Screen for screening. Further verification with Elitest in serial interpretation will enhance the PPV.


Assuntos
Pneumonia Intersticial Progressiva dos Ovinos , Doenças dos Ovinos , Vírus Visna-Maedi , Ovinos , Animais , Análise de Classes Latentes , Teorema de Bayes , Estudos Retrospectivos , Pneumonia Intersticial Progressiva dos Ovinos/diagnóstico , Pneumonia Intersticial Progressiva dos Ovinos/epidemiologia , Ensaio de Imunoadsorção Enzimática/veterinária , Doenças dos Ovinos/diagnóstico , Doenças dos Ovinos/epidemiologia
2.
Viruses ; 14(8)2022 08 01.
Artigo em Inglês | MEDLINE | ID: mdl-36016323

RESUMO

The canonical function of lentiviral Vif proteins is to counteract the mutagenic potential of APOBEC3 antiviral restriction factors. However, recent studies have discovered that Vif proteins from diverse HIV-1 and simian immunodeficiency virus (SIV) isolates degrade cellular B56 phosphoregulators to remodel the host phosphoproteome and induce G2/M cell cycle arrest. Here, we evaluate the conservation of this activity among non-primate lentiviral Vif proteins using fluorescence-based degradation assays and demonstrate that maedi-visna virus (MVV) Vif efficiently degrades all five B56 family members. Testing an extensive panel of single amino acid substitution mutants revealed that MVV Vif recognizes B56 proteins through a conserved network of electrostatic interactions. Furthermore, experiments using genetic and pharmacologic approaches demonstrate that degradation of B56 proteins requires the cellular cofactor cyclophilin A. Lastly, MVV Vif-mediated depletion of B56 proteins induces a potent G2/M cell cycle arrest phenotype. Therefore, remodeling of the cellular phosphoproteome and induction of G2/M cell cycle arrest are ancient and conserved functions of lentiviral Vif proteins, which suggests that they are advantageous for lentiviral pathogenesis.


Assuntos
HIV-1 , Vírus Visna-Maedi , Animais , Evolução Biológica , Pontos de Checagem do Ciclo Celular , Produtos do Gene vif/genética , Produtos do Gene vif/metabolismo , HIV-1/genética , HIV-1/metabolismo , Ovinos , Vírus Visna-Maedi/metabolismo , Produtos do Gene vif do Vírus da Imunodeficiência Humana/metabolismo
3.
Braz J Microbiol ; 53(3): 1723-1730, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35478313

RESUMO

Visna-maedi is a multisystemic and progressive inflammatory disease caused by a non-oncogenic retrovirus (Visna-maedi virus, VMV). An outbreak of visna-maedi occurred in Southern Brazil in sheep with clinical signs of blindness and stumbling gait. At post-mortem examination, all animals had similar lesions, including heavy non-collapsed lungs and multifocal yellow areas in the cerebral white matter, affecting mainly the periventricular region. These lesions corresponded histologically to lymphocytic interstitial pneumonia and histiocytic periventricular encephalitis surrounding areas of necrosis, in addition to significant demyelination in the brain. Serology was performed in all the sheep from the flock and 14% were seropositive for VMV. The presence of VMV was confirmed through PCR and partial sequencing of the 5'LTR. Sequencing demonstrated that the virus had 89.7 to 90.0% of nucleotide identity with VMV strains reported in the USA. This is the first description of clinical disease related to VMV in Brazil leading to economic losses. This study calls for the need to implement control measures to prevent the spread of small ruminant lentiviruses in Brazil.


Assuntos
Pneumonia Intersticial Progressiva dos Ovinos , Vírus Visna-Maedi , Visna , Animais , Brasil/epidemiologia , Surtos de Doenças/veterinária , Pneumonia Intersticial Progressiva dos Ovinos/epidemiologia , Pneumonia Intersticial Progressiva dos Ovinos/prevenção & controle , Ovinos , Visna/epidemiologia , Vírus Visna-Maedi/genética
4.
Can Vet J ; 63(4): 391-399, 2022 04.
Artigo em Inglês | MEDLINE | ID: mdl-35368401

RESUMO

Digital radiography and ultrasonographic images were used in this case series to evaluate 4 ewes from a single flock for chronic weight loss and ill-thrift. On examination, all displayed tachypnea, dyspnea, coughing, and normothermia with abnormal thoracic auscultations. Three of the 4 animals were diagnosed with chronic respiratory disease associated with Maedi-visna (MV) infection confirmed via serologic testing. Diagnostic thoracic imaging identified characteristics consistent with pathological lesions associated with interstitial pneumonia in the 3 MV affected animals; these findings were absent in the animal that tested negative for MV. Key clinical message: Diagnostic imaging may be useful to clinicians looking to obtain further visualization of lung pathologies and as a reliable means of detecting thoracic lesions indicative of interstitial pneumonia on-farm. These results can be used to aid the practitioner in determining appropriate further diagnostic testing and treatment strategies while awaiting confirmatory test results for diagnosis of MV.


Résultats de l'échographie et de la radiographie numérique chez des ovins atteints d'une maladie clinique associée à une infection à lentivirus des petits ruminants. La radiographie numérique et les images échographiques ont été utilisées dans cette série de cas pour évaluer quatre brebis d'un seul troupeau présentant une perte de poids chronique et un retard de croissance. À l'examen, tous les animaux présentaient une tachypnée, une dyspnée, une toux et étaient normothermiques avec des auscultations thoraciques anormales. Trois des quatre animaux ont été diagnostiqués avec une maladie respiratoire chronique associée à une infection Maedi-visna (MV) confirmée via des tests sérologiques. L'imagerie thoracique diagnostique a identifié des caractéristiques compatibles avec des lésions pathologiques associées à une pneumonie interstitielle chez les trois animaux atteints de MV; ces résultats étaient absents chez l'animal qui a été testé négatif pour MV.Message clinique clé :L'imagerie diagnostique peut être utile aux cliniciens qui cherchent à obtenir une visualisation plus poussée des pathologies pulmonaires et comme un moyen fiable de détecter les lésions thoraciques indiquant une pneumonie interstitielle à la ferme. Ces résultats peuvent être utilisés pour aider le praticien à déterminer d'autres tests de diagnostic appropriés et des stratégies de traitement en attendant les résultats des tests de confirmation pour le diagnostic de MV.(Traduit par Dr Serge Messier).


Assuntos
Infecções por Lentivirus , Doenças dos Ovinos , Vírus Visna-Maedi , Animais , Feminino , Infecções por Lentivirus/veterinária , Intensificação de Imagem Radiográfica , Ruminantes , Ovinos , Doenças dos Ovinos/diagnóstico por imagem , Ultrassonografia/veterinária
5.
Microb Pathog ; 165: 105467, 2022 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-35257804

RESUMO

Maedi is a lentiviral disease characterized by progressive interstitial pneumonia with humoural as well as cell mediated immune response. The present investigation was designed to detect the presence of MVV in different biological samples and to evaluate the immune response in naturally MVV infected sheep and goats. Total of 701 biological samples (289 lung tissues, 233 blood, 54 brain tissues, 74 mammary gland tissues and 51 joint tissues were screened for the MVV by nested PCR. MVV nucleic acid was detected in 10.41% of samples and it was observed that sheep samples showed positivity of 8.7% and goat samples 12.6%. Blood samples showed highest positivity (14.59%) followed by joint tissue (13.72), lungs (8.6%), mammary gland (8.1%) and brain (1.85%). MVV p28 antigen was detected in the cytoplasm of mononuclear cells, particularly in the macrophages of lungs and lymph nodes. Antibodies against SRLVs were detected by cELISA and seroprevalence of 19.58% was observed in both sheep and goats serum samples. The seropositivity was higher in sheep (22.9%) as compared to the goats (15.59%). IHC was done to identify the nature of the immune cells infiltrated in the MVV infected tissues and it was observed that B cells, CD8+ and macrophages were the predominant immune cells infiltrated in the lungs showing MVV infection. Expression of the cytokines was assessed by real time PCR and it was observed that expression of IL-10, IFN-γ, TNFα, IL-4, IL-2 and IL6 was down regulated in most of the cases but few samples showed upregulation. In conclusion, MVV is circulating in the sheep and goat population of the India and the disease causes altered immune response in the animal which may make the infected animals more prone to other infectious diseases.


Assuntos
Pneumonia Intersticial Progressiva dos Ovinos , Vírus Visna-Maedi , Animais , Cabras , Imunidade , Pneumonia Intersticial Progressiva dos Ovinos/patologia , Estudos Soroepidemiológicos , Ovinos
6.
J Med Microbiol ; 71(2)2022 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-35144720

RESUMO

Maedi-visna (MV) is a lentiviral disease of sheep responsible for severe production losses in affected flocks. There are no vaccination or treatment options with control reliant on test and cull strategies. The most common diagnostic methods used at present are combination ELISAs for Gag and Env proteins with virus variability making PCR diagnostics still largely an experimental tool. To assess variability in viral loads and diagnostic tests results, serology, DNA and RNA viral loads were measured in the blood of 12 naturally infected rams repeatedly blood sampled over 16 months. Six animals tested negative in one or more tests at one or more time points and would have been missed on screening programmes reliant on one test method or a single time point. In addition the one animal homozygous for the 'K' allele of the TMEM154 E35K SNP maintained very low viral loads in all assays and apparently cleared infection to below detectable limits at the final time point it was sampled. This adds crucial data to the strong epidemiological evidence that this locus represents a genuine resistance marker for MV infection and is a strong candidate for selective breeding of sheep for resistance to disease.


Assuntos
Proteínas de Membrana/genética , Pneumonia Intersticial Progressiva dos Ovinos , Ovinos/virologia , Visna , Alelos , Animais , Resistência à Doença , Estudos Longitudinais , Masculino , Pneumonia Intersticial Progressiva dos Ovinos/diagnóstico , Pneumonia Intersticial Progressiva dos Ovinos/genética , Polimorfismo de Nucleotídeo Único , Ovinos/genética , Carga Viral , Visna/diagnóstico , Visna/genética , Vírus Visna-Maedi
7.
Viruses ; 13(10)2021 10 13.
Artigo em Inglês | MEDLINE | ID: mdl-34696484

RESUMO

Small ruminant lentiviruses (SRLV) are economically important viral pathogens of sheep and goats. SRLV infection may interfere in the innate and adaptive immunity of the host, and genes associated with resistance or susceptibility to infection with SRLV have not been fully recognized. The presence of animals with relatively high and low proviral load suggests that some host factors are involved in the control of virus replication. To better understand the role of the genes involved in the host response to SRLV infection, RNA sequencing (RNA-seq) method was used to compare whole gene expression profiles in goats carrying both a high (HPL) and low (LPL) proviral load of SRLV and uninfected animals. Data enabled the identification of 1130 significant differentially expressed genes (DEGs) between control and LPL groups: 411 between control and HPL groups and 1434 DEGs between HPL and LPL groups. DEGs detected between the control group and groups with a proviral load were found to be significantly enriched in several gene ontology (GO) terms, including an integral component of membrane, extracellular region, response to growth factor, inflammatory and innate immune response, transmembrane signaling receptor activity, myeloid differentiation primary response gene 88 (MyD88)-dependent toll-like receptor signaling pathway as well as regulation of cytokine secretion. Our results also demonstrated significant deregulation of selected pathways in response to viral infection. The presence of SRLV proviral load in blood resulted in the modification of gene expression belonging to the toll-like receptor signaling pathway, the tumor necrosis factor (TNF) signaling pathway, the cytokine-cytokine receptor interaction, the phagosome, the Ras signaling pathway, the phosphatidylinositol 3-kinase (PI3K)/protein kinase B (AKT) (PI3K-Akt) signaling pathway and rheumatoid arthritis. It is worth mentioning that the most predominant in all pathways were genes represented by toll-like receptors, tubulins, growth factors as well as interferon gamma receptors. DEGs detected between LPL and HPL groups were found to have significantly enriched regulation of signaling receptor activity, the response to toxic substances, nicotinamide adenine dinucleotide (NADH) dehydrogenase complex assembly, cytokine production, vesicle, and vacuole organization. In turn, the Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway tool classified DEGs that enrich molecular processes such as B and T-cell receptor signaling pathways, natural killer cell-mediated cytotoxicity, Fc gamma R-mediated phagocytosis, toll-like receptor signaling pathways, TNF, mammalian target of rapamycin (mTOR) signaling and forkhead box O (Foxo) signaling pathways, etc. Our data indicate that changes in SRLV proviral load induced altered expression of genes related to different biological processes such as immune response, inflammation, cell locomotion, and cytokine production. These findings provide significant insights into defense mechanisms against SRLV infection. Furthermore, these data can be useful to develop strategies against SRLV infection by selection of animals with reduced SRLV proviral concentration that may lead to a reduction in the spread of the virus.


Assuntos
Vírus da Artrite-Encefalite Caprina/genética , Cabras/virologia , Vírus Visna-Maedi/genética , Imunidade Adaptativa/genética , Animais , Expressão Gênica/genética , Perfilação da Expressão Gênica/métodos , Regulação da Expressão Gênica/genética , Doenças das Cabras/virologia , Cabras/genética , Interações entre Hospedeiro e Microrganismos/genética , Imunidade Inata/genética , Infecções por Lentivirus/veterinária , Lentivirus Ovinos-Caprinos/genética , Provírus/genética , Análise de Sequência de RNA , Transcriptoma/genética , Carga Viral/métodos , Replicação Viral
8.
J Vet Sci ; 22(6): e66, 2021 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-34697919

RESUMO

BACKGROUND: Maedi/Visna virus (MVV) is a contagious viral pathogen that causes considerable economic losses to the sheep industry worldwide. OBJECTIVES: In China, MVV has been detected in several regions, but its molecular characteristics and genetic variations were not thoroughly investigated. METHODS: Therefore, in this study, we conducted next-generation sequencing on an MVV strain obtained from northwest China to reveal its genetic evolution via phylogenetic analysis. RESULTS: A MVV strain obtained from Inner Mongolia (NM) of China was identified. Sequence analysis indicated that its whole-genome length is 9193 bp. Homology comparison of nucleotides between the NM strain and reference strains showed that the sequence homology of gag and env were 77.1%-86.8% and 67.7%-75.5%, respectively. Phylogenetic analysis revealed that the NM strain was closely related to the reference strains isolated from America, which belong to the A2 type. Notably, there were 5 amino acid insertions in variable region 4 and a highly variable motif at the C-terminal of the surface glycoprotein (SU5). CONCLUSIONS: The present study is the first to show the whole-genome sequence of an MVV obtained from China. The detailed analyses provide essential information for understanding the genetic characteristics of MVV, and the results enrich the MVV library.


Assuntos
Pneumonia Intersticial Progressiva dos Ovinos , Doenças dos Ovinos , Vírus Visna-Maedi , Animais , China/epidemiologia , Sequenciamento de Nucleotídeos em Larga Escala/veterinária , Filogenia , Pneumonia Intersticial Progressiva dos Ovinos/virologia , Ovinos , Doenças dos Ovinos/virologia , Vírus Visna-Maedi/genética
9.
Int J Mol Sci ; 22(18)2021 Sep 11.
Artigo em Inglês | MEDLINE | ID: mdl-34575988

RESUMO

Maedi-Visna-like genotype A strains and Caprine arthritis encephaltis-like genotype B strains are small ruminant lentiviruses (SRLV) which, for incompletely understood reasons, appear to be more virulent in sheep and goats, respectively. A 9-month in vivo infection experiment using Belgian genotype A and B SRLV strains showed that almost all homologous (genotype A in sheep; genotype B in goats) and heterologous (genotype A in goats; genotype B in sheep) intratracheal inoculations resulted in productive infection. No differences in viremia and time to seroconversion were observed between homologous and heterologous infections. Higher viral loads and more severe lesions in the mammary gland and lung were however detected at 9 months post homologous compared to heterologous infection which coincided with strongly increased IFN-γ mRNA expression levels upon homologous infection. Pepscan analysis revealed a strong antibody response against immune-dominant regions of the capsid and surface proteins upon homologous infection, which was absent after heterologous infection. These results inversely correlated with protection against virus replication in target organs and observed histopathological lesions, and thus require an in-depth evaluation of a potential role of antibody dependent enhancement in SRLV infection. Finally, no horizontal intra- and cross-species SRLV transmission to contact animals was detected.


Assuntos
Vírus da Artrite-Encefalite Caprina/fisiologia , Genótipo , Doenças das Cabras/imunologia , Cabras , Imunidade Humoral , Pneumonia Intersticial Progressiva dos Ovinos/imunologia , Ovinos , Replicação Viral/imunologia , Vírus Visna-Maedi/fisiologia , Animais , Anticorpos Antivirais/imunologia , Feminino , Doenças das Cabras/genética , Doenças das Cabras/patologia , Doenças das Cabras/virologia , Cabras/imunologia , Cabras/virologia , Pulmão/imunologia , Pulmão/patologia , Pulmão/virologia , Glândulas Mamárias Animais/imunologia , Glândulas Mamárias Animais/patologia , Glândulas Mamárias Animais/virologia , Pneumonia Intersticial Progressiva dos Ovinos/genética , Pneumonia Intersticial Progressiva dos Ovinos/patologia , Pneumonia Intersticial Progressiva dos Ovinos/virologia , Ovinos/imunologia , Ovinos/virologia , Especificidade da Espécie , Carga Viral/imunologia
10.
Viruses ; 13(9)2021 08 27.
Artigo em Inglês | MEDLINE | ID: mdl-34578292

RESUMO

Small ruminant lentiviruses (SRLVs) infections lead to chronic diseases and remarkable economic losses undermining health and welfare of animals and the sustainability of farms. Early and definite diagnosis of SRLVs infections is the cornerstone for any control and eradication efforts; however, a "gold standard" test and/or diagnostic protocols with extensive applicability have yet to be developed. The main challenges preventing the development of a universally accepted diagnostic tool with sufficient sensitivity, specificity, and accuracy to be integrated in SRLVs control programs are the genetic variability of SRLVs associated with mutations, recombination, and cross-species transmission and the peculiarities of small ruminants' humoral immune response regarding late seroconversion, as well as intermittent and epitope-specific antibody production. The objectives of this review paper were to summarize the available serological and molecular assays for the diagnosis of SRLVs, to highlight their diagnostic performance emphasizing on advantages and drawbacks of their application, and to discuss current and future perspectives, challenges, limitations and impacts regarding the development of reliable and efficient tools for the diagnosis of SRLVs infections.


Assuntos
Infecções por Lentivirus/diagnóstico , Infecções por Lentivirus/imunologia , Lentivirus/genética , Lentivirus/imunologia , Ruminantes/virologia , Testes Sorológicos/veterinária , Animais , Vírus da Artrite-Encefalite Caprina/genética , Vírus da Artrite-Encefalite Caprina/imunologia , Doenças das Cabras/diagnóstico , Doenças das Cabras/virologia , Cabras/virologia , Lentivirus/classificação , Lentivirus/isolamento & purificação , Soroconversão , Testes Sorológicos/métodos , Ovinos/virologia , Doenças dos Ovinos/diagnóstico , Doenças dos Ovinos/virologia , Virologia/métodos , Vírus Visna-Maedi/genética , Vírus Visna-Maedi/imunologia
11.
J Biol Chem ; 296: 100045, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33465707

RESUMO

The mammalian apolipoprotein B mRNA-editing enzyme catalytic polypeptide-like 3 (APOBEC3 or A3) family of cytidine deaminases restrict viral infections by mutating viral DNA and impeding reverse transcription. To overcome this antiviral activity, most lentiviruses express a viral accessory protein called the virion infectivity factor (Vif), which recruits A3 proteins to cullin-RING E3 ubiquitin ligases such as cullin-5 (Cul5) for ubiquitylation and subsequent proteasomal degradation. Although Vif proteins from primate lentiviruses such as HIV-1 utilize the transcription factor core-binding factor subunit beta as a noncanonical cofactor to stabilize the complex, the maedi-visna virus (MVV) Vif hijacks cyclophilin A (CypA) instead. Because core-binding factor subunit beta and CypA are both highly conserved among mammals, the requirement for two different cellular cofactors suggests that these two A3-targeting Vif proteins have different biochemical and structural properties. To investigate this topic, we used a combination of in vitro biochemical assays and in vivo A3 degradation assays to study motifs required for the MVV Vif to bind zinc ion, Cul5, and the cofactor CypA. Our results demonstrate that although some common motifs between the HIV-1 Vif and MVV Vif are involved in recruiting Cul5, different determinants in the MVV Vif are required for cofactor binding and stabilization of the E3 ligase complex, such as the zinc-binding motif and N- and C-terminal regions of the protein. Results from this study advance our understanding of the mechanism of MVV Vif recruitment of cellular factors and the evolution of lentiviral Vif proteins.


Assuntos
Vírus Visna-Maedi/metabolismo , Produtos do Gene vif do Vírus da Imunodeficiência Humana/metabolismo , Sequência de Aminoácidos , Proteínas Culina/metabolismo , Ciclofilina A/metabolismo , Ligação Proteica , Domínios Proteicos , Proteólise , Zinco/metabolismo , Produtos do Gene vif do Vírus da Imunodeficiência Humana/química
12.
PLoS One ; 15(9): e0238781, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32911525

RESUMO

Maedi-visna (MV) is a complex lentiviral disease syndrome characterised by long immunological and clinical latencies and chronic progressive inflammatory pathology. Incurable at the individual level, it is widespread in most sheep-keeping countries, and is a cause of lost production and poor animal welfare. Culling seropositive animals is the main means of control, but it might be possible to manage virus transmission effectively if its epidemiology was better quantified. We derive a mathematical epidemiological model of the temporal distributions of seroconversion probabilities and estimate susceptibility, transmission rate and latencies in three serological datasets. We demonstrate the existence of epidemiological latency, which has not explicitly been recognised in the SRLV literaure. This time delay between infection and infectiousness apparently exceeds the delay between infection and seroconversion. Poor body condition was associated with more rapid seroconversion, but not with a higher probability of infection. We estimate transmission rates amongst housed sheep to be at about 1,000 times faster than when sheep were at grass, when transmission was negligible. Maternal transmission has only a small role in transmission, because lambs from infected ewes have a low probability of being infected directly by them, and only a small proportion of lambs need be retained to maintain flock size. Our results show that MV is overwhelmingly a disease of housing, where sheep are kept in close proximity. Prevalence of MV is likely to double each year from an initial low incidence in housed flocks penned in typically-sized groups of sheep (c. 50) for even a few days per year. Ewes kept entirely at grass are unlikely to experience transmission frequently enough for MV to persist, and pre-existing infection should die out as older ewes are replaced, thereby essentially curing the flock.


Assuntos
Pneumonia Intersticial Progressiva dos Ovinos/transmissão , Vírus Visna-Maedi/patogenicidade , Animais , Monitoramento Epidemiológico/veterinária , Incidência , Modelos Teóricos , Pneumonia Intersticial Progressiva dos Ovinos/imunologia , Pneumonia Intersticial Progressiva dos Ovinos/virologia , Prevalência , Soroconversão , Ovinos/imunologia , Ovinos/virologia , Doenças dos Ovinos/epidemiologia , Vírus Visna-Maedi/imunologia
13.
J Dairy Sci ; 103(10): 9213-9223, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32828507

RESUMO

Maedi-Visna virus (MVV) and Mycobacterium avium ssp. paratuberculosis (MAP) are two pathogens that cause chronic, production-limiting diseases in dairy sheep. Although they are present worldwide, there are no detailed reports on their actual effects on milk traits in the literature. This study was designed to investigate the effects of test positivity to MVV and MAP on ovine milk yield, composition and coagulation properties, and curd-firming over time (CFt) variables in clinically healthy animals at the field level. The additive genetic variation and heritabilities of MVV and MAP positivity were also estimated. Milk samples were collected from 1,079 Sarda sheep kept on 23 farms, and pedigree information was obtained from the flock book. Milk yield was also recorded on the sampling date. Positivity for MVV and MAP was determined from milk samples using indirect ELISA test kits. Milk composition traits were measured by spectroscopy, milk coagulation properties were measured with a Formagraph (Foss Italia, Padua, Italy), and CFt traits were calculated using the data from the Formagraph diagram. The effects of MVV and MAP positivity on milk traits were determined through a set of mixed linear models, which took into account various sources of variation, such as days in milk, parity, and flock effects, and included the effects (positive or negative) of the 2 pathogens. A Bayesian threshold sire model with sire relationship was used to estimate genetic variation and heritability. The overall animal prevalence of MVV-positive ewes was 43.6%; on only 1 farm of the 23 tested were all sampled ewes negative. An overall animal prevalence of 10.6% was recorded for MAP, with 4 farms at 0%. Positivity for MVV significantly affected the logarithmic score of the bacterial count, curd firmness after 30 min and 45 min, and the curd-firming instant rate constant. We found significant effects of MAP infection on milk composition, pH, and rennet coagulation time. The mean of the posterior distributions of heritability estimates on the liability scale was 0.15 for MAP and 0.07 for MVV. Our results demonstrate that only a few traits are negatively affected by MVV and MAP positivity, and that there is exploitable genetic variation in MVV and MAP susceptibility in dairy sheep.


Assuntos
Leite , Mycobacterium avium subsp. paratuberculosis , Paratuberculose/diagnóstico , Doenças dos Ovinos/virologia , Vírus Visna-Maedi , Visna/diagnóstico , Animais , Teorema de Bayes , Queijo/análise , Ensaio de Imunoadsorção Enzimática/veterinária , Feminino , Predisposição Genética para Doença , Padrões de Herança , Itália , Modelos Lineares , Leite/química , Paratuberculose/genética , Paratuberculose/fisiopatologia , Paridade , Gravidez , Ovinos , Doenças dos Ovinos/diagnóstico , Visna/genética , Visna/fisiopatologia
14.
Braz. J. Vet. Res. Anim. Sci. (Online) ; 57(2): [e164278], mai. 2020. tab, graf
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-1097349

RESUMO

The present study aimed to estimate the prevalence of antibodies against Brucella ovis-epididymitis, smooth-Brucella, leptospirosis, toxoplasmosis and Maedi-visna in sheep slaughtered in Minas Gerais, Brazil and to study their simultaneous occurrence, including caseous lymphadenitis, at sheep and flock levels. The study was conducted at a sheep slaughterhouse with Federal Inspection Service. Sera from 594 animals from 21 flocks were collected, in 2007. The agar gel immunodiffusion (AGID) was employed to detect anti-B. ovis and anti-Maedi Visna antibodies, whereas Rose Bengal (RB) and the 2-mercaptoethanol test (2ME) were used to test anti-smooth Brucella antibodies. For the detection of anti-Leptospiraantibodies, sera were examined by microscopic agglutination test (MAT), while for the detection of IgG antibodies to Toxoplasma gondii ELISA was used. Prevalence of antibodies against smooth Brucella, B. ovis-epididimitis, Leptospiraspp., toxoplasmosis and Maedi-Visna found in sheep from Minas Gerais was 0.00%, 24.04%, 25.96%, 10.46% and 3.08%, respectively; whereas the seroprevalence in flocks was 0.00%, 80.95%, 90.48%, 71.43% and 23.81%, respectively. Moreover, when data on antibodies anti-Corynebacterium pseudotuberculosis, previously obtained, were included, about 60% of the flocks showed animals that were exposed to four or more of the studied agents. However, only 25.47% of the sheep exhibited simultaneously antibodies against more than one pathogen. Thus, data from the present study on sheep slaughtered in Minas Gerais, Brazil, showed no antibodies to smooth-Brucella and a low frequency of antibodies anti-Maedi Visna lentivirus, and a high and widespread seroprevalence of B. ovis, Leptospira spp., and T. gondii among animals and flocks.(AU)


O presente estudo teve como objetivo estimar a prevalência de anticorpos contra Brucella ovis (epididimite ovina), Brucellalisa, leptospirose, toxoplasmose e Maedi-visna em ovinos abatidos em Minas Gerais, Brasil, e estudar sua ocorrência simultânea, incluindo linfadenite caseosa, nos ovinos e nos rebanhos. O estudo foi realizado em um abatedouro de ovinos com Serviço de Inspeção Federal. Soros de 594 animais de 21 rebanhos foram coletados, em 2007. A imunodifusão em gel de ágar (IDGA) foi empregada para detectar anticorpos anti-B. ovis e anticorpos anti-Maedi Visna, enquanto o teste do antígeno acidificado tamponado (AAT) e o teste de 2-mercaptoetanol (2ME) foram utilizados para testar anticorpos anti-Brucella lisa. Para a detecção de anticorpos anti-Leptospira, os soros foram examinados pelo teste de aglutinação microscópica (MAT), enquanto que para a detecção de anticorpos IgG para Toxoplasma gondii, foi usado o ELISA. A prevalência de anticorpos anti-Brucella lisa, B. ovis, Leptospira spp., toxoplasmose e Maedi-Visna encontrados em ovinos de Minas Gerais foi de 0,00%, 24,04%, 25,96%, 10,46% e 3,08%, respectivamente; enquanto a soroprevalência em rebanhos foi de 0,00%, 80,95%, 90,48%, 71,43% e 23,81%, respectivamente. Além disso, quando dados de anticorpos anti-Corynebacterium pseudotuberculosis, previamente obtidos, foram incluídos, cerca de 60% dos rebanhos apresentaram animais expostos a quatro ou mais dos agentes estudados. No entanto, apenas 25,47% dos ovinos exibiram simultaneamente anticorpos contra mais de um patógeno. Assim, os dados do presente estudo sobre ovinos abatidos em Minas Gerais, Brasil, mostram que ausência de anticorpos anti-Brucella lisa e baixa frequência de anticorpos anti-Maedi Visna, e uma soroprevalência alta e generalizada de B. ovis, Leptospira spp. e T. gondii entre animais e rebanhos.(AU)


Assuntos
Animais , Ovinos/microbiologia , Ovinos/virologia , Toxoplasmose , Vírus Visna-Maedi , Brucella ovis , Leptospirose , Estudos Soroepidemiológicos
15.
BMC Vet Res ; 15(1): 109, 2019 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-30967151

RESUMO

BACKGROUND: In order to characterize the complete range of lesions, especially minimal, affecting mammary gland and viral antigen distribution and target cells using immunohistochemistry in naturally Visna/maedi (VM) 84 infected sheep were studied, forty-four from flocks with clinical cases (A) and 35 randomly sampled from two abattoirs (B) together with five negative controls (C). An immunocytochemistry technique was developed and further milk samples (n = 39) were used to study viral excretion, carrier cells and the role of milk and colostrum in the transmission of the disease. RESULTS: All sheep from group C and three sheep from group B were negative to VM in tissue sections by histopathology, immunohistochemistry and PCR, and also in serum using ELISA. Several degrees of CD3 + lymphocytic interstitial mastitis were observed in groups A and B: minimal (+) n = 26 sheep; moderate (++), n = 32 and severe (+++), n = 12. No differences in lesion distribution were observed between groups A and B. Viral presence was confirmed by immunohistochemistry using two different antibodies and/or PCR in every tissue with lesions while serology was negative in six sheep with lesions. Two milk samples taken from milk tanks from two flocks from group A and fourteen milk samples from 29 infected sheep from group B were positive to VM (most of them from animals with moderate and severe lesions). Positivity was only found in macrophages, even in focal and minimal lesions, while no positivity was observed in epithelial or any other cells in either tissue and milk samples. CONCLUSIONS: This new observation of the minimal lesions described in this work increased the prevalence of VM lesions in mammary gland up to 90.9% and VM should be considered as a differential diagnosis when minimal interstitial lesions are detected. A high prevalence of VM was observed in intensive milk-producing sheep, ELISA serology did not detect as positivity all infected animals, while histology, IHC or PCR showed higher sensitivity. The cytological technique developed was very useful in milk-cell studies using hematoxylin and eosin and immunocytochemistry. Viral detection in milk samples (16/39) confirms a potential but limited role of milk/colostrum in viral transmission.


Assuntos
Glândulas Mamárias Animais/virologia , Leite/virologia , Vírus Visna-Maedi , Visna/patologia , Animais , Feminino , Glândulas Mamárias Animais/patologia , Pneumonia Intersticial Progressiva dos Ovinos/patologia , Pneumonia Intersticial Progressiva dos Ovinos/virologia , Reação em Cadeia da Polimerase/veterinária , Ovinos/virologia , Visna/virologia
16.
BMC Genomics ; 20(1): 62, 2019 Jan 18.
Artigo em Inglês | MEDLINE | ID: mdl-30658565

RESUMO

BACKGROUND: MicroRNAs (miRNAs) are short endogenous, single-stranded, noncoding small RNA molecules of approximately 22 nucleotides in length. They regulate gene expression posttranscriptionally by silencing mRNA expression, thus orchestrating many physiological processes. The Small Ruminant Lentiviruses (SRLV) group includes the Visna Maedi Virus (VMV) and Caprine Arthritis Encephalitis (CAEV) viruses, which cause a disease in sheep and goats characterized by pneumonia, mastitis, arthritis and encephalitis. Their main target cells are from the monocyte/macrophage lineage. To date, there are no studies on the role of miRNAs in this viral disease. RESULTS: Using RNA-seq technology and bioinformatics analysis, the expression levels of miRNAs during different clinical stages of infection were studied. A total of 212 miRNAs were identified, of which 46 were conserved sequences in other species but found for the first time in sheep, and 12 were completely novel. Differential expression analysis comparing the uninfected and seropositive groups showed changes in several miRNAs; however, no significant differences were detected between seropositive asymptomatic and diseased sheep. The robust increase in the expression level of oar-miR-21 is consistent with its increased expression in other viral diseases. Furthermore, the target prediction of the dysregulated miRNAs revealed that they control genes involved in proliferation-related signalling pathways, such as the PI3K-Akt, AMPK and ErbB pathways. CONCLUSIONS: To the best of our knowledge, this is the first study reporting miRNA profiling in sheep in response to SRLV infection. The known functions of oar-miR-21 as a regulator of inflammation and proliferation appear to be a possible cause of the lesions caused in the sheep's lungs. This miRNA could be an indicator for the severity of the lung lesions, or a putative target for therapeutic intervention.


Assuntos
Infecções por Lentivirus/veterinária , Pulmão/metabolismo , MicroRNAs/genética , Análise de Sequência de RNA/métodos , Doenças dos Ovinos/genética , Animais , Vírus da Artrite-Encefalite Caprina/fisiologia , Análise por Conglomerados , Feminino , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Interações Hospedeiro-Patógeno , Infecções por Lentivirus/genética , Infecções por Lentivirus/virologia , Pulmão/patologia , Pulmão/virologia , Ovinos , Doenças dos Ovinos/virologia , Vírus Visna-Maedi/fisiologia
17.
Viruses ; 10(12)2018 12 08.
Artigo em Inglês | MEDLINE | ID: mdl-30544780

RESUMO

Countries rely on good diagnostic tests and appropriate testing schemes to fight against economically important small ruminant lentivirus (SRLV) infections. We undertook an extensive comparative analysis of seven commercially available serological tests and one in-house real-time PCR (qPCR) detecting genotype A and B strains using a large panel of representative Belgian field samples and samples from experimentally infected sheep and goats. ELISAs generally performed well and detected seroconversion within three weeks post experimental infection. Two enzyme-linked immunosorbent assays (ELISAs) (Elitest and IDscreen® kits) showed the highest sensitivities (>96%) and specificities (>95%) in both species, and their combined use allowed to correctly identify the infection status of all animals. Individual agar gel immunodiffusion (AGIDs) kits lacked sensitivity, but interestingly, the combined use of both kits had a sensitivity and specificity of 100%. qPCRs detected SRLV infection before seroconversion at two weeks post infection and showed a specificity of 100%. Sensitivity however remained suboptimal at 85%. These results allow to propose a faster and cheaper diagnostic testing strategy for Belgium by combining a first ELISA screening, followed by confirmation of positive samples in AGID and/or a second ELISA. Since genotypes A and B strains are predominant in many countries, these results are interesting for other countries implementing SRLV control programs.


Assuntos
Doenças das Cabras/diagnóstico , Infecções por Lentivirus/veterinária , Técnicas de Diagnóstico Molecular/métodos , Testes Sorológicos/métodos , Doenças dos Ovinos/diagnóstico , Animais , Anticorpos Antivirais/sangue , Vírus da Artrite-Encefalite Caprina , Bélgica , Ensaio de Imunoadsorção Enzimática , Doenças das Cabras/virologia , Cabras , Imunodifusão , Infecções por Lentivirus/diagnóstico , Kit de Reagentes para Diagnóstico , Reação em Cadeia da Polimerase em Tempo Real , Sensibilidade e Especificidade , Soroconversão , Ovinos , Doenças dos Ovinos/virologia , Vírus Visna-Maedi
18.
Pesqui. vet. bras ; 38(6): 1203-1206, jun. 2018. tab
Artigo em Inglês | LILACS, VETINDEX | ID: biblio-955441

RESUMO

Bluetongue (BT) is an infectious and non-contagious disease of compulsory notification which may affect domestic and wild ruminants, transmitted by Culicoides spp. midges. Despite the high morbidity and mortality in sheep, role of wild animals in the BT cycle remains unclear. Caprine arthritis-encephalitis (CAE) and Maedi-Visna virus (MVV) have been reportedly found in goats and sheep, but not described in wildlife species. Accordingly, serum samples from 17 captive Barbary sheep (Ammotragus lervia) from Curitiba zoo, southern Brazil, were tested for bluetongue, caprine arthritis-encephalitis (CAE) and Maedi-Visna viruses by agar gel immunodiffusion (AGID) and enzyme linked immunosorbent assay (ELISA). Antibodies for bluetongue were observed in 6/17 (35.3%) Barbary sheep by AGID test and in 7/17 (41.2%) by ELISA. All samples were negative for the presence of antibodies against caprine arthritis-encephalitis (CAE) and Maedi-Visna viruses. These findings indicate that Barbary sheep may be infected by bluetongue virus and act as wildlife reservoir in both captive and free-range environments.(AU)


A língua azul é uma doença infecciosa e não contagiosa, de notificação obrigatória, que pode afetar ruminantes domésticos e silvestres, transmitida por mosquitos do gênero Culicoides spp. Apesar da alta morbidade e mortalidade em ovelhas, o papel de animais silvestres no ciclo do vírus da língua azul é desconhecido. A artrite encefalite caprina (CAE) e Maedi-visna vírus (MVV) tem sido encontrados em cabras e ovelhas, porém não há descrição em espécies selvagens. Amostras de soro de 17 aoudads (Ammotragus lervia), mantidos em cativeiro no Zoológico de Curitiba, Sul do Brasil, foram testadas para os vírus da língua azul, da artrite encefalite caprina (CAE) e Maedi-visna, utilizando imunodifusão em gel de ágar e o teste de ELISA (enzyme linked immunosorbent assay). Foram observados anticorpos para o vírus da língua azul em 35,3% (6/17) aoudads utilizando a imunodifusão em gel de ágar e 41,2% (7/17) no ELISA. Todas as amostras foram negativas para a presença de anticorpos contra os vírus da artrite encefalite caprina e Maedi-visna. Esses resultados indicam que os aoudads podem ser infectados pelo vírus da língua azul e atuar como um reservatório silvestre tanto em cativeiro quanto em vida livre.(AU)


Assuntos
Animais , Ruminantes/virologia , Ceratopogonidae/patogenicidade , Vírus Visna-Maedi/patogenicidade , Meningoencefalomielite Ovina
19.
Vet Res ; 49(1): 36, 2018 04 19.
Artigo em Inglês | MEDLINE | ID: mdl-29673399

RESUMO

Maedi-visna, a disease caused by small ruminant lentiviruses (SRLVs), is present in sheep from many countries, also including Germany. An amino acid substitution (E/K) at position 35 of the transmembrane protein 154 (TMEM154) as well as a deletion in the chemokine (C-C motif) receptor type 5 gene (CCR5) were reported to be associated with the serological MV status and/or the SRLV provirus concentration in North American sheep populations. The aim of this study was to test if those two gene variants might be useful markers for MV susceptibility in Germany. For this purpose, more than 500 sheep from 17 serologically MV positive German sheep flocks with different breed backgrounds were genotyped applying PCR-based methods. Both, crosstab and non-parametric analyses showed significant associations of the amino acid substitution at position 35 of TMEM154 with the serological MV status (cut-off-based classification) and the median MV ELISA S/P value in all samples and in two of the four analyzed breed subsets. The deletion in the CCR5 promoter did not show a consistent association with serological MV status or median ELISA S/P value. It can be concluded that the amino acid substitution at position 35 of TMEM154 is a promising marker for breeding towards a lower number of serologically MV positive sheep in German flocks, at least in flocks of the Texel breed, while this remains questionable for the deletion in the CCR5 promoter. The findings of this study still need to be verified in additional sheep breeds.


Assuntos
Predisposição Genética para Doença/genética , Proteínas de Membrana/genética , Pneumonia Intersticial Progressiva dos Ovinos/epidemiologia , Receptores CCR5/genética , Vírus Visna-Maedi/fisiologia , Visna/epidemiologia , Sequência de Aminoácidos , Substituição de Aminoácidos , Animais , Feminino , Marcadores Genéticos/genética , Alemanha , Pneumonia Intersticial Progressiva dos Ovinos/genética , Pneumonia Intersticial Progressiva dos Ovinos/virologia , Deleção de Sequência , Ovinos , Visna/genética , Visna/virologia
20.
Prev Vet Med ; 151: 13-20, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29496101

RESUMO

Maedi-Visna virus (MVV) and caprine arthritis encephalitis virus (CAEV) are two prototype members of the group of small ruminant lentiviruses (SRLVs). Both result in progressive and persistent infections of sheep and goats that impact animal health and cause economic losses. In Belgium, the sheep and goat sector is small and consists mostly of hobbyist farmers keeping few animals. A voluntary control program however exists, but less than 2% of the farmers participate to the program. The current lack of SRLV seroprevalence data and knowledge on risk factors related to SRLV seropositivity in this hobbyist sector makes it difficult to evaluate the risk of SRLV transmission from non-certified to SRLV free certified farms. We performed a nationwide SRLV seroprevalence study based on a stratified sampling proportional to the number of sheep and goat holders per province. Randomly selected sheep and goat owners were invited to participate and subject to a short questionnaire to collect information about flock size, animal health condition, age, flock constitution and housing conditions. Samples were collected from maximum 7 animals per farm and tested in a commercial ELISA. In total, we received samples from 87 sheep and 76 goat farms. Sheep flocks showed an overall seroprevalence of 9% (CI 95%: 5-15) and a between-herd seroprevalence of 17% (CI 95%:11-27). Seroprevalence at animal level in goat flocks was 6% (CI 95%: 3-12) and the between-herd seroprevalence was 13% (CI 95%: 7-23). Multiple sheep and goat breeds were found SRLV seropositive. Answers provided during the questionnaire confirmed the mostly hobbyist nature of the sector and showed that more than 65% of sheep and goat farmers had never heard of the disease. The only risk factor found to be related to SRLV seroprevalence was flock size. Herds of more than 10 goats had significantly higher chance to harbor seropositive animals (OR: 4.36; CI: 1.07; 17.73). In conclusion, it was shown that participants to the SRLV free certification program are at risk for reintroduction of the disease in their herds since SRLVs are present on about 15%-20% of non-certified farms. Except from flock size, no clear risk factors were found that are helpfull to identify flocks at risk. Greater effort should be made to inform sheep and goat farmers about the existence and consequences of this disease in order to promote the voluntary control program and further reduce the disease prevalence.


Assuntos
Vírus da Artrite-Encefalite Caprina/fisiologia , Doenças das Cabras/epidemiologia , Infecções por Lentivirus/veterinária , Doenças dos Ovinos/epidemiologia , Vírus Visna-Maedi/fisiologia , Animais , Bélgica/epidemiologia , Doenças das Cabras/virologia , Cabras , Infecções por Lentivirus/epidemiologia , Infecções por Lentivirus/virologia , Prevalência , Fatores de Risco , Estudos Soroepidemiológicos , Ovinos , Doenças dos Ovinos/virologia
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